Symptom attribution in first episode psychosis: a cortical thickness study

Area of Science:

• Neuroscience
• Psychiatry
• Brain Imaging

Background:

• Insight, the ability to attribute symptoms to a mental disorder, is crucial for treatment adherence in psychosis.
• Previous research linked orbitofrontal cortex (OFC) gray matter volume to overall symptom attribution in first-episode schizophrenia.
• The neural basis for attributing specific psychotic symptoms and regions beyond the OFC remain unclear.

Purpose of the Study:

• To investigate the neural correlates of attributing specific psychotic symptoms (delusions, hallucinations, flat affect, asociality) in first-episode psychosis (FEP).
• To determine if brain regions beyond the OFC are involved in symptom attribution.
• To explore whether common or distinct neural systems underlie the attribution of different psychotic symptoms.

Main Methods:

• Magnetic resonance imaging (MRI) was used to assess cortical thickness in 52 individuals with FEP.
• The Scale for Assessment of Unawareness of Mental Disorder was employed to rate symptom attribution for hallucinations, delusions, flat affect, and asociality.
• Cortical thickness data were regressed against symptom attribution ratings across 81,924 vertices.

Main Results:

• Misattribution of delusions was associated with OFC thickness (Brodmann's area 11/47).
• Misattribution of delusions, flat affect, and asociality correlated with dorsolateral prefrontal cortex (BA 9/46) thinness.
• Differential associations between symptom attribution and cortical thickness/thinness were observed across frontal, temporal, parietal, and occipital regions.

Conclusions:

• The OFC plays a selective role in the misattribution of delusions in FEP.
• Cortical thickness variations in multiple brain regions suggest partially independent neural systems for attributing different psychotic symptoms.
• These findings advance our understanding of the neurobiology of insight in psychosis.